|
: Percept Mot Skills 1999 Oct;89(2):371-80 |
Hand preference as related to development and behavior in infancy.
Tirosh E, Stein M, Harel J, Scher A
Hannah Khoushy Child Development Center, Bnai Zion Medical Center, Bruce Rappaport Faculty of Medicine, Technion
Israel Institute of Technology, Haifa. etirosh@tx.technion
55 healthy infants were assessed for their developmental and behavioral patterns at the age of 9 mo. Hand preference
was assessed at 20 mo. of age. The distribution of hand preference showed 12 were right-handed, 11 left-handed
and 23 ambidextrous. This distribution appears shifted more to the left than that reported for older children.
Although their data were based on different tests not appropriate for 9-mo.-old infants, ambidexterity appeared
to reflect part of the hand-preference continuum. No significant relationship between hand preference and developmental
attainments was noted. Perhaps a larger sample would provide a clear developmental behavioral pattern and hand
preference in infancy.
PMID: 10597571, UI: 20065439
|
: Brain Lang 1999 Dec;70(3):504-17 |
Left-handedness and achievements in foreign language studies.
Lamm O, Epstein R
School of Education, University of Haifa, Haifa, Israel. orenl@construct.haifa.ac.il
Studies of brain lateralization lend support to the hypothesis that language-motor functions in left-handers are
differently organized from those in right-handers. However, the implications of these differences regarding cognitive
functioning are as yet subject to controversy. This concerns all hypotheses raised and empirical data collected
over the years. Although it was suggested that left-handers are at higher risk of having language and reading deficits,
empirical data from clinical and nonclinical populations are inconclusive at the present time. No effort, however,
has been invested in examining possible differences in academic studies of foreign languages according to handedness.
Here we report data indicating inferior achievements of left-handed native Hebrew speakers in studies of English
as a foreign language. Left-handed pupils significantly more than right-handers were placed in lower level English
classes and had more difficulties in applying orthographic-phonological mapping rules in reading English words
and pseudowords. However, left-handers' difficulties in this task were not correlated with their performance in
a word recognition task. It is thus suggested that the "common symptom" of poor word reading in left-handers
indicates different processing failures in different left-handers, some of which impede the buildup of an internal
representational system of mapping orthography to phonology and some of which concern mainly the precision of word
production. Copyright 1999 Academic Press.
PMID: 10600231, UI: 20069062
|
: Am J Public Health 1999 Dec;89(12):1873-5 |
The association between switching hand preference and the declining prevalence
of left-handedness with age.
Galobardes B, Bernstein MS, Morabia A
Division of Clinical Epidemiology, University Hospital of Geneva, Switzerland. bruna.galobardes@hcuge.ch
OBJECTIVES: This study determined the prevalence of left-handedness and of switching hand preference among innately
left-handed subjects. METHODS: Subjects of Swiss nationality (n = 1692), participating in a population-based survey
in Geneva, Switzerland, completed a questionnaire on innate hand preference and current hand preference for writing.
RESULTS: From 35 to 44 years of age to 65 to 74 years of age, the prevalence of innate left-handedness declined
from 11.9% to 6.2% (trend P = .007). In these same age groups, the proportion of innately left-handed subjects
who switched to the right hand for writing increased from 26.6% to 88.9% (trend P = .0001). CONCLUSIONS: Across
generations, we found an increase in the prevalence of switching hand preference among innately left-handed subjects.
This phenomenon could be explained by social and parental pressure to use the right hand.
PMID: 10589322, UI: 20056700
|
: Am J Psychiatry 1999 Nov;156(11):1730-5 |
Superior temporal gyrus volume abnormalities and thought disorder in left-handed
schizophrenic men.
Holinger DP, Shenton ME, Wible CG, Donnino R, Kikinis R, Jolesz FA, McCarley RW
Department of Psychiatry, Harvard Medical School, Boston, USA. dorothy_holinger@caregroup.harvard.edu
OBJECTIVE: Studies of schizophrenia have not clearly defined handedness as a differentiating variable. Moreover,
the relationship between thought disorder and anatomical anomalies has not been studied extensively in left-handed
schizophrenic men. The twofold purpose of this study was to investigate gray matter volumes in the superior temporal
gyrus of the temporal lobe (left and right hemispheres) in left-handed schizophrenic men and left-handed comparison
men, in order to determine whether thought disorder in the left-handed schizophrenic men correlated with tissue
volume abnormalities. METHOD: Left-handed male patients (N = 8) with DSM-III-R diagnoses of schizophrenia were
compared with left-handed comparison men (N = 10) matched for age, socioeconomic status, and IQ. Magnetic resonance
imaging (MRI) with a 1.5-T magnet was used to obtain scans, which consisted of contiguous 1.5-mm slices of the
whole brain. MRI analyses (as previously defined by the authors) included the anterior, posterior, and total superior
temporal gyrus in both the left and right hemispheres. RESULTS: There were three significant findings regarding
the left-handed schizophrenic men: 1) bilaterally smaller gray matter volumes in the posterior superior temporal
gyrus (16% smaller on the right, 15% smaller on the left); 2) a smaller volume on the right side of the total superior
temporal gyrus; and 3) a positive correlation between thought disorder and tissue volume in the right anterior
superior temporal gyrus. CONCLUSIONS: These results suggest that expression of brain pathology differs between
left-handed and right-handed schizophrenic men and that the pathology is related to cognitive disturbance.
PMID: 10553736, UI: 20019164
|
Neurosci Lett 1999 Aug 20;271(2):89-92 |
Cortical asymmetries of the human somatosensory hand representation in
right- and left-handers.
Soros P, Knecht S, Imai T, Gurtler S, Lutkenhoner B, Ringelstein EB, Henningsen H
Department of Neurology, University of Munster, Germany. soros@uni-muenster.de
Hemispheric asymmetry is known for higher brain functions like language and attention. We tested whether such an
asymmetry also exists in the representation of elementary sensory functions. Magnetic source imaging was used to
compare the cortical somatosensory hand representation in seven right- and five left-handed individuals. In all
right-handers the representation of the dominant hand was larger than the contralateral one in the corresponding
hemispheres. In contrast, only two out of five left-handers revealed a larger representation of the dominant left
hand compared to the right one. In agreement with previous findings on the lateralization of language and attention,
there is a strong correlation between handedness and the extent of the cortical hand representation in right-,
but not in left-handers. We conclude that a profound functional hemispheric asymmetry also exists in primary sensory
cortices.
PMID: 10477109, UI: 99404759
|
J Hand Surg [Br] 1999 Aug;24(4):421-5 |
A comparison of dominant and non-dominant hand strengths.
Armstrong CA, Oldham JA
Centre for Rehabilitation Science, University of Manchester, UK.
This study compares dominant and non-dominant hand strength in both right- and left-handed participants. Maximum
voluntary contraction (MVC) of the first dorsal interosseous (FDI) muscle, power grip strength and pulp-to-pulp
pinch strength were assessed under carefully controlled conditions. No significant differences were observed between
dominant and non-dominant hands in left-handed participants for all tests. Small but significant differences (0.1-3%)
were observed between dominant and non-dominant hands in right-handed participants for all three tests. These differences
were much smaller than those reported in other studies. Furthermore, considerable variability was observed in the
relative strengths of the two hands for each participant. We conclude that clinicians must be cautious when using
the '10% rule' to make comparisons between injured and uninjured hands.
PMID: 10473148, UI: 99400127
|
: J Basic Clin Physiol Pharmacol 1999;10(2):147-50 |
Left-handed women have earlier age of menopause.
Dane S, Reis N, Pasinliogu T
Department of Physiology, Medical Faculty, Ataturk University, Erzurum, Turkey.
Association between handedness and age of menopause was assessed. A significant difference in the mean age of menopause
was found between left-handed and right-handed women. There was a significant correlation between age at menopause
and hand preference in right-handed women. These findings suggest that earlier age of menopause in left-handed
women may be due to a more active and effective immune system in left-handers.
PMID: 10444716, UI: 99373742
|
: Neuropsychologia 1999 Jul;37(8):895-903 |
Hemispheric asymmetry and interhemispheric transfer in reaching programming.
Velay JL, Benoit-Dubrocard S
Lab. Neurobiologie Integrative et Adaptative, UMR CNRS 6562, Universite de Provence, Marseille, France. velay@newsup.univ-mrs.fr
The purpose of this study was to explore the intrahemispheric processes and the interhemispheric transfer that
occur during the programming of a pointing movement. Twenty five subjects participated in this experiment: 12 were
right-handed (Rhr), 12 left-handed (Lhr), and 1 was left-handed with a posterior callosal lesion. The task consisted
in producing an open loop pointing response toward a visual target appearing briefly on the right or the left of
a central fixation point. Reaction times (RTs) were shorter for the Rhrs when reaching with the left hand than
with the right hand. No such hand-related difference was observed in the Lhrs. The left hand advantage indicates
that one process was faster in the right hemisphere of Rhrs. This faster process appears not to be visual but motor
or visuomotor. For either hand, responses were faster when the target appeared in the visual field homolateral
to the pointing hand (uncrossed condition) than when it appeared contralaterally to the hand (crossed condition).
The crossed vs uncrossed difference did not vary between Rhrs and Lhrs or between the hands. The transfer time
between the hemispheres was symmetrical whatever its direction. The partially callosotomized left-handed subject
was two-fold slower than the control Lhrs. His uncrossed responses were faster than the crossed ones, but his interhemispheric
transfer time was very asymmetrical: it was normal from right to left hemisphere but was highly increased in the
opposite direction. An attempt at modelling the RT data is proposed and the possibility of different callosal locations
for the interhemispheric transfer is discussed.
PMID: 10426515, UI: 99353587
|
: Behav Genet 1999 Mar;29(2):103-14 |
Left-handedness as a function of sex, maternal versus paternal inheritance,
and report bias.
Annett M
Department of Psychology, University of Leicester, UK. "M.Annett">doc@le.ac.uk
The right-shift (RS) theory suggests that sex differences for handedness are due to the displacement of a chance
distribution of asymmetry farther to the right in females than males by about 20%. An analysis of studies in the
literature shows that when handedness is assessed by self-report, paired samples of males and females differ for
incidence of left-handedness as predicted, but for parents assessed by indirect-report, there are fewer left-handed
mothers than expected. When handedness is assessed by self-report in both generations, the RS genetic model successfully
predicts the distribution in families. It is also successful at different levels of criterion from left-writing
to non-right-handedness. The RS predictions are not always consistent with the findings of studies that depended
on indirect report of parental handedness. When parental incidences are low the proportion of left-handed children
in the families of left-handed mothers is higher than expected. When parental incidences are high, predictions
for the families of left-handed mothers are excellent, but the percentage of left-handed children in the families
of left-handed fathers is lower than expected. Data for all indirect-report studies are combined to test the idea
that the chief cause of poor fit is underreporting of left-handed mothers by right-handed children. Transfer of
right-handed children from R x R to R x L families, thereby raising the percentage of left-handed mothers by about
1%, is sufficient to give good fits to RS predictions for both sexes.
Publication Types:
· Review
· Review, tutorial
PMID: 10405459, UI: 99333846
|
Radiat Med 1999 Mar-Apr;17(2):145-9 |
Functional magnetic resonance imaging of auditory cortex: with special
reference to the side of aural stimulation.
Maehara T, Ozaki H, Wakabayashi C, Iizuka Y, Hosokawa A
Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
PURPOSE: To determine whether left- or right-side uniaural stimulation produces different fMRI activation patterns.
METHODS: Subjects were 12 volunteers (8 right-handed, 4 left-handed) with normal hearing. Functional imaging using
FE-type multishot echo planar imaging was obtained in the axial plane during pure-tone and pseudoword tasks. Auditory
stimuli were presented to each ear individually. In pure-tone tasks, subjects heard clustered sequences at 2000
Hz. In pseudoword tasks, subjects heard spoken Japanese syllables. The numbers of activated pixels in the auditory
cortex were counted and compared for pure-tone and pseudoword tasks, as was activation according to the side of
aural stimulation. RESULTS: In right-handed subjects, prominent activation in pure-tone tasks was noted in the
dominant hemisphere in 100% of cases and was unrelated to the side of the stimulation. In pseudoword tasks, prominent
activation was noted on the side contralateral to the stimulus in 62.5-100% of cases. In left-handed subjects,
prominent activation was noted on the side contralateral to the stimulus in both pure-tone and pseudoword tasks.
CONCLUSION: Left- and right-side stimulation produced differences in fMRI responses, especially between pure-tone
and pseudoword tasks. Moreover, right-handedness and left-handedness affected results. This type of auditory fMRI
may be a noninvasive indicator of language lateralization.
PMID: 10399783, UI: 99327982
|
Cortex 1999 Feb;35(1):123-8 |
Handedness and season of birth: a gender-invariant relation.
Martin M, Jones GV
University of Oxford, UK. maryanne.martin@psy.ox.ac.uk
In an earlier study, Dellatolas, Curt and Lellouch (1991) concluded that handedness is not related to season of
birth. However, post-hoc exploration of their and other sets of data has shown that there is an apparent tendency
for left-handedness to be more prevalent in the period March-July than in the period August-February. The present
work tested this seasonal hypothesis prospectively among university students. It was found that the proportion
of all left-handed participants who were born in the period March-July was indeed significantly greater than the
proportion of all right-handed participants who were born in the same period. Furthermore, the pattern of seasonal
influence upon handedness did not vary significantly between females and males. The relation between handedness
and season of birth may be linked to seasonal variation in other factors such as the incidence of infectious agents.
PMID: 10213539, UI: 99228553
|
: Neurology 1999 Mar 23;52(5):1038-43 |
Cerebral lateralization of language in normal left-handed people studied
by functional MRI.
Pujol J, Deus J, Losilla JM, Capdevila A
Magnetic Resonance Center of Pedralbes, Spain.
OBJECTIVE: To use functional MRI (fMRI) to further define the occurrence of left-hemisphere, bilateral, and right-hemisphere
language in a normal left-handed population. METHODS: A total of 100 healthy volunteers, consisting of 50 left-handed
subjects and a reference group of 50 right-handed subjects, were studied by fMRI of the frontal cortex during silent
word generation. RESULTS: Ninety-six percent of right-handed subjects showed fMRI changes lateralized to the left
hemisphere, whereas 4% showed a bilateral activation pattern. In contrast, left-hemisphere lateralization occurred
in 76% of left-handers, bilateral activation in 14%, and right-hemisphere lateralization in the remaining 10%.
The predominance of right-hemisphere activation, however, was weak in these cases; only a single left-handed subject
(2%) showed complete right-hemisphere lateralization. CONCLUSIONS: Silent word generation lateralizes to the left
cerebral hemisphere in both handedness groups, but right-hemisphere participation is frequent in normal left-handed
subjects. Exclusive right-hemisphere activation rarely occurred in the frontal lobe region studied.
PMID: 10102425, UI: 99200548
|
Ann N Y Acad Sci 1998 Nov 30;855:575-8 |
Functional lateralization of human gustatory cortex related to handedness
disclosed by fMRI study.
Cerf B, Lebihan D, Van de Moortele PF, Mac Leod P, Faurion A
Laboratoire de Neurobiologie Sensorielle, E.P.H.E., Massy, France. cerf@citi2.fr
Ten healthy subjects aged 20-25 including five right-handed and five left-handed according to the Dellatolas test
participated in this functional magnetic resonance imaging (fMRI) study. A 3 Tesla whole-body MR scanner allowed
echo planar imaging (EPI)-64 x 64 pixels, repetition time (TR) = 6 s, field of view (FOV) = 20 x 20 cm2--associated
to acute anatomical localization of activated foci (256 x 256 pixels). Subjects were bilaterally stimulated with
NaCl 85 mM, aspartame 2 mM, quinine hydrochloride 1 mM, glycyrrhizic acid 0.5 mM, guanosine monophosphate 1 mM
and D-threonine 250 mM alternating with water. Stimuli and rinse were continuously pushed as bolus of 50 microliters
every 3 s to the subject's mouth through microsyringes. We detected brain activated areas by correlation of the
MR signal to an on-line perception profile recorded for each experiment and each subject with the finger-span method.
We found most activations in the insula and the perisylvian region in agreement with previous electrophysiological
studies on monkeys and clinical reports in humans. The superior part of the insula was bilaterally activated, in
accordance with a whole-mouth stimulation. A striking lateralization related to handedness was found in a lower
part of the insula. This projection in the dominant hemisphere, located in the same coronal plane as the upper
insular activation, is the first evidence of a functional lateralization of brain processing involved in taste
perception.
PMID: 9929653, UI: 99128514
|
: Percept Mot Skills 1998 Dec;87(3 Pt 1):1015-34 |
Lateralized ultradian rhythms: evidence from tactile discrimination of
either hand.
Meier-Koll A
Department of Psychology, University of Konstanz, Germany.
Endogenous ultradian rhythms with periods of one or a few hours affect not only on physiological and behavioural
functions but also perception and cognition. In particular, lateralized ultradian rhythms which seem to operate
separately in the right and left hemispheres of the brain can be monitored by testing the tactile discrimination
of the contralateral hand. The present paper is based on two subsequent studies: First, ultradian rhythms in tactile
discrimination of either hand were examined in German subjects under laboratory conditions. Considerably different
ultradian periods of right and left-handed tactile error rate were found in men but not in women. In a second study,
a group of Kenyan Masai shepherds were tested while the subjects were leading herds on daily feeding routes through
a savanna habitat. They showed ultradian periods of about 2 hours in tactile discrimination of either hand. Since
the right hemisphere is specialized for visuospatial, the left for verbal processing lateralized ultradian rhythms
may serve for a long-scale timing of neural processes underlying spatial and semantic mapping of the environment.
Sex difference in German subjects and lateral differences found in left-handed (right-hemispheric) ultradian rhythms
of German and Masai subjects are discussed from this point of view.
Publication Types:
· Clinical trial
· Randomized controlled trial
PMID: 9885074, UI: 99100812
|
: Brain 1998 Dec;121 ( Pt 12):2369-79 |
Morphology of the planum temporale and corpus callosum in left handers
with evidence of left and right hemisphere speech representation.
Moffat SD, Hampson E, Lee DH
Department of Psychology, University of Western Ontario, London, Canada.
In the present study we investigated planum temporale asymmetry and corpus callosum morphology in a sample of young
adult left-handed males, using MRI. Two subgroups of left-handed males were identified on the basis of their differing
speech lateralization patterns, which were inferred from results of the Fused Dichotic Words Test. These individuals
then underwent MRI in order to obtain area measurements of the left and right planum temporale and the midsagittal
corpus callosum. Comparisons between these left-handed males and an archival sample of age-matched right-handed
males were also performed. Results demonstrated a strong leftward asymmetry in the planum temporale among subjects
with left-hemisphere speech representation, regardless of handedness, but no consistent planum temporale asymmetry
among subjects with right hemisphere speech representation. The results suggest that reversed speech lateralization
is not necessarily accompanied by a concomitant reversal of planum temporale asymmetry. Examination of callosal
areas revealed that left-handed subjects with left hemisphere speech functions had a larger corpus callosum than
either left-handed subjects with right hemisphere speech functions or right-handed subjects. Increased interhemispheric
communication may be required when the neural systems underlying speech and handedness are represented in opposite
hemispheres.
PMID: 9874487, UI: 99089883
|
: J Neurosurg 1998 Dec;89(6):962-70 |
Preoperative predictors of anterior temporal language areas.
Schwartz TH, Devinsky O, Doyle W, Perrine K
Department of Neurological Surgery, The Neurological Institute of New York, Columbia-Presbyterian Medical Center,
New York 10032, USA. ths4@columbia.edu
OBJECT: Although it is known that 5 to 10% of patients have language areas anterior to the rolandic cortex, many
surgeons still perform standard anterior temporal lobectomies for epilepsy of mesial onset and report minimal long-term
dysphasia. The authors examined the importance of language mapping before anterior temporal lobectomy. METHODS:
The authors mapped naming, reading, and speech arrest in a series of 67 patients via stimulation of long-term implanted
subdural grids before resective epilepsy surgery and correlated the presence of language areas in the anterior
temporal lobe with preoperative demographic and neuropsychometric data. Naming (p < 0.03) and reading (p <
0.05) errors were more common than speech arrest in patients undergoing surgery in the anterior temporal lobe.
In the approximate region of a standard anterior temporal lobectomy, including 2.5 cm of the superior temporal
gyrus and 4.5 cm of both the middle and inferior temporal gyrus, the authors identified language areas in 14.5%
of patients tested. Between 1.5 and 3.5 cm from the temporal tip, patients who had seizure onset before 6 years
of age had more naming (p < 0.02) and reading (p < 0.01) areas than those in whom seizure onset occurred
after age 6 years. Patients with a verbal intelligence quotient (IQ) lower than 90 had more naming (p < 0.05)
and reading (p < 0.02) areas than those with an IQ higher than 90. Finally, patients who were either left handed
or right hemisphere memory dominant had more naming (p < 0.05) and reading (p < 0.02) areas than right-handed
patients with bilateral or left hemisphere memory lateralization. Postoperative neuropsychometric testing showed
a trend toward a greater decline in naming ability in patients who were least likely to have anterior language
areas, that is, those with higher verbal IQ and later seizure onset. CONCLUSIONS: Preoperative identification of
markers of left hemisphere damage, such as early seizure onset, poor verbal IQ, left handedness, and right hemisphere
memory dominance should alert neurosurgeons to the possibility of encountering essential language areas in the
anterior temporal lobe (1.5-3.5 cm from the temporal tip). Naming and reading tasks are required to identify these
areas. Whether removal of these areas necessarily induces long-term impairment in verbal abilities is unknown;
however, in patients with a low verbal IQ and early seizure onset, these areas appear to be less critical for language
processing.
PMID: 9833823, UI: 99049569
|
Eur J Neurosci 1998 Aug;10(8):2731-7 |
Influence of handedness on peripheral auditory asymmetry.
Khalfa S, Veuillet E, Collet L
CNRS UPRESA 5020, Perception et Mecanismes Auditifs, Pavillon U, Hopital Edouard Herriot, 3, Place d'Arsonval,
69003 Lyon, France. skhalfa@olfac.univ-lyon1.fr
It is well established that in humans many differences between right- and left-handers, anatomical, physiological
and functional, exist. Left- and mixed-handedness is associated with greater bihemispheric representation of cognitive
functions than in right-handers. Several studies indicate a left-right asymmetry in the function of hearing pathways
between cochlea and auditory cortex, and furthermore, that this asymmetry is associated with handedness. Our investigation
focuses on the medial olivo-cochlear system, which has been demonstrated to be more effective in the right than
left ear in right-handers. The aim of the study was to investigate this auditory efferent system asymmetry according
to handedness, gender, eyedness, footedness and the presence of spontaneous otoacoustic emissions. The medial efferent
system has been found to be more effective in the right than left ear in right-handers, while functioning symmetrically
in left-handers. Furthermore, the olivo-cochlear system, assumed to be involved in basic language processing, shows
an asymmetrical pattern of functioning influenced by handedness as well as by hemispheric language representation.
Reverse medial efferent system asymmetry was observed in left-handers compared to that in right-handers, on condition
that only left-handed males were considered, or that the left-handers were also left-eyed, or that spontaneous
otoacoustic emissions were present in the left ear of the left-handers, or when only left-handers without mixed-handers
were considered.
PMID: 9767403, UI: 99145686
|
: Am J Med Genet 1998 Sep 7;81(5):420-7 |
Evidence for linkage to psychosis and cerebral asymmetry (relative hand
skill) on the X chromosome.
Laval SH, Dann JC, Butler RJ, Loftus J, Rue J, Leask SJ, Bass N, Comazzi M, Vita A, Nanko S, Shaw S, Peterson
P, Shields G, Smith AB, Stewart J, DeLisi LE, Crow TJ
Department of Psychiatry, Warneford Hospital, Oxford, UK.
The hypothesis that psychosis arises as a part of the genetic diversity associated with the evolution of language
generates the prediction that illness will be linked to a gene determining cerebral asymmetry, which, from the
evidence of sex chromosome aneuploidies, is present in homologous form on the X and Y chromosomes. We investigated
evidence of linkage to markers on the X chromosome in 1) 178 families multiply affected with schizophrenia or schizoaffective
disorder with a series of 16 markers spanning the centromere (study 1), and 2) 180 pairs of left-handed brothers
with 14 markers spanning the whole chromosome (study 2). In study 1, excess allele-sharing was observed in brother-brother
pairs (but not brother-sister or a small sample of sister-sister pairs) over a region of approximately 20 cM, with
a maximum LOD score of 1.5 at DXS991. In study 2, an association between allele-sharing and degree of left-handedness
was observed extending over approximately 60 cM, with a maximum lod score of 2.8 at DXS990 (approximately 20 cM
from DXS991). Within the overlap of allele-sharing is located a block in Xq21 that transposed to the Y chromosome
in recent hominid evolution and is now represented as two segments on Yp. In one of two XX males with psychosis
we found that the breakpoint on the Y is located within the distal region of homology to the block in Xq21. These
findings are consistent with the hypothesis that an X-Y homologous determinant of cerebral asymmetry carries the
variation that contributes to the predisposition to psychotic illness.
PMID: 9754628, UI: 98425599
|
: Electroencephalogr Clin Neurophysiol 1998 Jul;108(4):355-60 |
The AEP T-complex to synthesised musical tones: left-right asymmetry in
relation to handedness and hemisphere dominance.
Jones SJ, Byrne C
Department of Clinical Neurophysiology, The National Hospital for Neurology and Neurosurgery, London, UK. sjjones@ion.ucl.ac.uk
Auditory evoked potentials were recorded to onset and offset of synthesised instrumental tones in 40 normal subjects,
20 right-handed for writing and 20 left-handed. The majority of both groups showed a T-complex which was larger
at the right temporal electrode (T4) than the left (T3). In the T4-T3 difference waveforms, the mean potential
between latencies of 130 and 165 ms was negative in all right-handed subjects except two for whom the waveforms
were marginally positive-going. Amongst the left-handers, however, this converse asymmetry was seen in 7 subjects,
5 of them more than 2 standard deviations from the mean of the right-handed group. The degree of asymmetry was
not significantly correlated with the degree of left-handedness according to the Edinburgh Handedness Inventory.
Asymmetry of the T-complex to instrumental tones appears to reflect the lateralisation of auditory 'musical' processing
in the temporal cortex, confirming evidence from other sources including PET that this is predominantly right-sided
in the majority of individuals. The proportion of left-handers showing the converse laterality is roughly in accordance
with those likely to be right-hemisphere-dominant for language. If linguistic and 'musical' processes are consistently
located in opposite hemispheres, AEPs to complex tones may prove a useful tool in establishing functional lateralisation.
PMID: 9714377, UI: 98378179
|
: Brain Lang 1998 Sep;64(2):182-214 |
Do the hands talk on mind's behalf? Differences in language ability between
left- and right-handed children.
Natsopoulos D, Kiosseoglou G, Xeromeritou A, Alevriadou A
University of Thessaloniki, Hellas, Greece.
Two hundred seventy children of school age, 135 of whom were left-handed and an equivalent number of whom were
right-handed, have been examined in the present study using a test battery of nine language ability measures: Vocabulary,
Similarities, Comprehension (WISC-R), Deductive Reasoning, Inductive Reasoning, Sentence Completion, Comprehension
of Sentential Semantics, Comprehension of Syntax, and Text Processing. The data analysis has indicated that: (1)
One-factor solution applies both to the right- and left-handed population according to Standard Error Scree Method
(Zoski & Jurs, 1996) with regard to language ability measures. (2) Handedness discriminates between right-handers
(superior) and left-handers (inferior) in language ability. (3) There have been subgroups of left-handed children
who differ in language ability distribution compared with right-handed children according to Hierarchical Cluster
Analysis. (4) Extreme versus mild bias to hand preference and hand skill do not differentiate performance subgroups
neither within the left-handed nor within the right-handed main group. (5) Sex and familial sinistrality do not
affect performance. The results are discussed in relation to (a) "human balanced polymorphism" theory
advocated by Annett (mainly Annett, 1985, 1993a; Annett & Manning, 1989), (b) potential pathology (mainly Bishop,
1984, 1990a; Coren & Halpern, 1991; Satz, Orsini, Saslow & Henry, 1985) and "developmental instability"
(Yeo, Gangestad & Daniel, 1993), and delay of left-hemisphere maturation in left-handed individuals (Geschwind
& Galaburda, 1985a,b, 1987), by pointing out the strength and weaknesses of these theoretical approaches in
accounting for the present data. Copyright 1998 Academic Press.
PMID: 9710489, UI: 98378386
|
Shinrigaku Kenkyu 1998 Apr;69(1):39-46 |
[Processing of emotional kanji words in the right hemisphere and the effect
of handedness on the processing].
[Article in Japanese]
Nagae S
Department of Psychology, Faculty of Education, Fukuoka University of Education, Munakata.
Experimental and clinical evidence indicates that the right hemisphere plays a special role in the processing of
non-verbal emotional material. The possibility that verbal material may also be similarly processed in the hemisphere
was investigated with a reading aloud task, with unilateral tachistoscopic presentation of emotional and non-emotional
kanji words. Right-handed subjects, both male and female, participated in Experiment 1 and right and left-handed
subjects of both sexes in Experiment 2. Results of Experiment 1 showed that response to non-emotional kanji words
were more accurate in the right visual field than in the left, but no difference was found for emotional words.
Results of Experiment 2 showed the word-emotionality by visual-field interaction effect on accuracy of both right-
and left-handed subjects, but the effect was more pronounced for the right-handed. The results suggest that the
right hemisphere processes emotional kanji words just as well as the left.
PMID: 9691353, UI: 98356358
|
Behav Genet 1998 May;28(3):187-95 |
Eye dominance in children: a longitudinal study.
Dellatolas G, Curt F, Dargent-Pare C, De Agostini M
INSERM U169, Recherches en Epidemiologie, Villejuif, France. dellatol@vjf.inserm.fr
In a sample of 807 normal preschool children aged from 3 to 6, examined eye dominance was not associated with the
declared eye dominance of their parents. Forty percent of the children showed left-eyedness. Eyedness was associated
with handedness and not significantly related to age group or sex. A strong relationship between the answers of
the two parents concerning eye preference was observed. Two hundred forty-four children were followed-up for 2
years. The examinations were carried out once every 6 months. Two thirds of the children showed perfect stability
in eye dominance. There was some evidence that stability in eye use tends to increase with age and to be lower
in left-handed children with left-handed parents. There is, at present, very little evidence of a positive association
between eye dominance in parents and that in their children.
PMID: 9670594, UI: 98335250
|
: J Cereb Blood Flow Metab 1998 Jul;18(7):735-41 |
Temporal patterns of evoked cerebral blood flow during reading.
Tiecks FP, Haberl RL, Newell DW
Department of Neurological Surgery, University of Washington, Harborview Medical Center, Seattle, USA.
This study describes the dynamics of flow activation by reading and investigates the potential use of repeated
flow velocity measurements for the lateralization of speech. Using simultaneous transcranial Doppler recordings
from both middle cerebral arteries and averaging techniques in 25 healthy volunteers, we describe the changes in
blood flow velocity caused by repetitive reading tasks of variable duration in comparison with a resting state.
Reading aloud evoked a characteristic temporal flow pattern in both hemispheres, consisting of three relative maxima
in flow velocity during and after activation. Flow velocities lower than baseline were common during longer lasting
activation. The amplitudes of two of the observed peaks decreased depending on the duration of the task. Reading
silently produced a markedly different temporal pattern of activation than reading aloud. There were individually
reproducible significant side to side differences. Right-handed persons (n = 15) almost without exception showed
a significantly higher increase in flow velocity on the left hemisphere (e.g., reading silently 8.7% versus 5.3%;
P < 0.0001). Three out of ten left-handed individuals, however, exhibited no significant side to side difference
or exhibited lateralization to the right during one or more of the tasks. These findings suggest that reading induces
task-specific temporal patterns of regional neuronal activity, which show habituation with longer duration of activation.
Additionally, the observed side to side differences could be useful to predict language dominance.
PMID: 9663503, UI: 98326636
|
: Neuropsychologia 1998 Mar;36(3):201-7 |
Pitch perception: a difference between right- and left-handed listeners.
Laguitton V, Demany L, Semal C, Liegeois-Chauvel C
Clinique Neurologique, Centre Hospitalier Universitaire Pontchaillou, Rennes, France.
Various results indicate that the perception of a complex tone's "virtual" pitch is generally lateralized
in the right cerebral hemisphere. The primary aim of this work was to test the hypothesis that this is not the
case for the "spectral" pitch percepts induced by complex tones. Forty right-handed and 18 left-handed
listeners were monaurally presented with pairs of successive tones made up of n consecutive equal-amplitude harmonics
of a missing fundamental (F0). n varied from two to four across subjects. In "test" conditions, the paired
tones differed in F0 but the spectral components of the tone with the lower F0 were higher in frequency than the
corresponding components of the other tone (except for one component, which was identical). The subjects had to
say if, from one tone to the other, pitch rose or fell. From such judgements, one could infer that the pitch dominantly
perceived in each tone was a virtual pitch (corresponding to F0) or a spectral pitch (i.e., the pitch of a single
spectral component, or a perceptual quality corresponding to the centroid of the power spectrum). For n = 2, the
results indicated that virtual pitch was less salient than spectral pitch; the opposite occurred for n = 3 and
n = 4. The ear (left or right) to which the stimuli were presented had some influence on the judgements, in the
expected direction. However, this influence was not a robust one. Unexpectedly, a reliable effect of the listeners'
handedness was observed: for each value of n, the judgements indicating virtual pitch perception were less frequent
in the left-handers than in the right-handers. Discrimination performances measured in "control" conditions
showed that the handedness factor was not confounded with a factor of frequency discrimination ability.
PMID: 9622185, UI: 98283528
|
Science 1998 May 8;280(5365):902-5 |
Modular organization of cognitive systems masked by interhemispheric integration.
Baynes K, Eliassen JC, Lutsep HL, Gazzaniga MS
Center for Neuroscience, University of California at Davis, Davis, CA 95616, USA. kbaynes@ucdavis.edu
After resection of the corpus callosum, V.J., a left-handed woman with left-hemisphere dominance for spoken language,
demonstrated a dissociation between spoken and written language. In the key experiment, words flashed to V.J.'s
dominant left hemisphere were easily spoken out loud, but could not be written. However, when the words were flashed
to her right hemisphere, she could not speak them out loud, but could write them with her left hand. This marked
dissociation supports the view that spoken and written language output can be controlled by independent hemispheres,
even though before her hemispheric disconnection, they appeared as inseparable cognitive entities.
Comments:
· Comment in: Science 1998 May 8;280(5365):827
|
: Mem Cognit 1998 Mar;26(2):193-200 |
Generalizing everyday memory: signs and handedness.
Martin M, Jones GV
Department of Experimental Psychology, University of Oxford, England. maryanne.martin@psy.ox.ac.uk
Memory for frequently encountered road signs was investigated. In Experiment 1, the average level of recall of
road sign features was found to be only 47%. In Experiment 2, more left-handed than right-handed people recalled
that a walking figure faces right on one sign, whereas more right-handed than left-handed people recalled that
a digging figure faces left on another sign. Performance thus reflected not a difference in level of mnemonic ability
between left-handed and right-handed groups but instead the compatibility between group and task. In Experiment
3, participants were asked to draw any figure walking and any figure digging, with a pattern of results similar
to that of Experiment 2. It is suggested that handedness effects in recall are mediated by motor imagery.
PMID: 9584428, UI: 98245407
|
Neuropsychologia 1998 Jan;36(1):37-43 |
Footedness is a better predictor than is handedness of emotional lateralization.
Elias LJ, Bryden MP, Bulman-Fleming MB
Department of Psychology, University of Waterloo, Ontario, Canada. ljelias@watarts.uwaterloo.ca
A tremendous amount of experimental work has attempted to identify reliable behavioural predictors of cerebral
lateralization. Preferred handedness has been the most popular predictor, but some recent reports suggest that
preferred footedness may serve as a more accurate predictor of functional laterality, especially in the left-handed
population. The present study sought to test this claim by selectively recruiting individuals with either 'crossed'
lateral preferences (right-handed and left-footed or left-handed and right-footed) or 'uncrossed' lateral preferences
(right-handed and right-footed or left-handed and left-footed). Lateralization of emotional perception was assessed
with two blocks of the dichotic Emotional Words Test (EWT), and lateral preference for both handedness and footedness
was assessed using self-report questionnaires. Ear advantage on the dichotic task varied significantly with preferred
foot (P=0.003), but not with preferred hand. Cerebral lateralization may be more related to footedness than to
other lateral preferences.
PMID: 9533385, UI: 98192055
|
: Brain Res Cogn Brain Res 1998 Jan;6(3):185-92 |
Right-handers and left-handers have different representations of their
own hand.
Gentilucci M, Daprati E, Gangitano M
Istituto di Fisiologia Umana, Universita di Parma, via Gramsci 14, I-43100 Parma, Italy. gentiluc@piruniv.cce.unipr.it
The visual control of our own hand when dealing with an object and the observation of interactions between other
people's hand and objects can be involved in the construction of internal representations of our own hand, as well
as in hand recognition processes. Therefore, a different effect on handedness recognition is expected when subjects
are presented with hands holding objects with either a congruent or an incongruent type of grip. Such an experiment
was carried out on right-handed and left-handed subjects. We expected that the different degree of lateralisation
in motor activities observed in the two populations [J. Herron, Neuropsychology of left-handedness, Academic Press,
New York, 1980.] could account for the construction of different internal hand representations. As previously found
[L.M. Parsons, Imaged spatial transformations of one's hands and feet, Cogn. Psychol., 19 (1987) 178-241.], in
order to identify handedness, subjects mentally rotated their own hand until it matched with the presented one.
This process was confirmatory, being preceded by an implicit visual analysis of the target hand. Presentation of
hands holding objects with congruent or incongruent types of grip influenced handedness recognition at different
stages in right-handed and left-handed subjects. That is, the mental rotation stage was affected in right-handed
subjects, whereas the initial phase of implicit hand analysis was affected in left-handed subjects. We suggest
that in handedness recognition, left-handers relied more on a pictorial hand representation, whereas right-handers
relied more on a pragmatic hand representation, probably derived from experience in the control of their own movements.
The use of different hand representations may be due to differential activation of temporal and premotor areas.
Publication Types:
· Clinical trial
PMID: 9479070, UI: 98147991